I also posted this in the YZ forum, but the WR bikes are the same so hopefully someone here can help me. I just bought a 99 YZ400, and the previous owner had just installed new front and rear sprockets. However, the chain was really loose. Today when I tried to tighten the bolts at the chain pullers, the bolts will only turn 1/8 either way (both of them do the same thing). Then they feel like they are going to snap if I push any further. I have loosened the "lock" nut that's against the rear arm, and I loosened the axle nut. My friend's bike (98 WR400) is parked next to mine, so I loosened his the same way and they turn very easily. I do not want to break these bolts off and have to deal with that. Any suggestions? Has anyone ever heard of this happening? It's like they are seized up in the hole or something.